Kos or Cos (English pronunciation:/kɒs/) (Greek: Κως, Greek pronunciation: [kos]) is a Greek island, part of the Dodecanese island chain in the southeastern Aegean Sea, off the Anatolian coast of Turkey. Kos is the third largest of the Dodecanese by area, after Rhodes and Karpathos; it has a population of 33,388 (2011 census), making it the second most populous of the Dodecanese, after Rhodes.[1] The island measures 40 by 8 kilometres (25 by 5 miles), and is 4 km (2 miles) from the coast of the ancient region of Caria in Turkey. Administratively, Kos constitutes a municipality within the Kos regional unit, which is part of the South Aegeanregion. The principal town of the island and seat of the municipality is Kos town.[2]

Tourism is the main industry in Kos,[citation needed] the island's beaches being the primary attraction. The main port and population centre on the island, Kos town, is also the tourist and cultural centre, with whitewashed buildings including many hotels, restaurants and a number of nightclubs forming the Kos town "barstreet". The seaside village of Kardamena is a popular resort for young holidaymakers (primarily from the United Kingdom and Scandinavia) and has a large number of bars and nightclubs.

The island was originally colonised by the Carians. The Dorians invaded it in the 11th century BC, establishing a Dorian colony with a large contingent of settlers from Epidaurus, whose Asclepius cult made their new home famous for its sanatoria. The other chief sources of the island's wealth lay in its wines and, in later days, in its silk manufacture.[14]

Proximity to the east gave the island first access to imported silk thread. Aristotle mentions silk weaving conducted by the women of the island.[16] Silk production of garments was conducted in large factories by women slaves.[17]

In the Hellenistic period, Kos attained the zenith of its prosperity. Its alliance was valued by the Ptolemaic kings of Egypt, who used it as a naval outpost to oversee the Aegean. As a seat of learning, it arose as a provincial branch of the museum of Alexandria, and became a favorite resort for the education of the princes of the Ptolemaic dynasty. During the Hellenistic age, there was a medical school; however, the theory that this school was founded by Hippocrates (see below) during the Classical age is an unwarranted extrapolation.[18]

Except for occasional incursions by corsairs and some severe earthquakes, the island has rarely had its peace disturbed. Following the lead of its larger neighbour, Rhodes, Kos generally displayed a friendly attitude toward the Romans; in 53 AD it was made a free city. It was known in antiquity for the manufacture of transparent light dresses, the coae vestes.[22] The island of Kos also featured a provincial library during the Roman period. The island first became a center for learning during the Ptolemaic dynasty, and Hippocrates, Apelles, Philitas and possibly Theocritus came from the area. An inscription lists people who made contributions to build the library in the 1st century AD.[23] One of the people responsible for the library's construction was the Kos doctor Gaiou Stertinou Xenofontos, who lived in Rome and was the personal physician of the Emperors Tiberius, Claudius, and Nero.[24]

The Ottoman Empire captured the island in early 1523.[25] The Ottomans ruled Kos for almost 400 years, until it was transferred to the Kingdom of Italy in 1912 after the Italo-Turkish War.[29] The Italians developed the infrastructures of the island, after the ruinous earthquake of 23 April 1933, which destroyed a great part of the old city and damaged many new buildings. Architect Rodolfo Petracco drew up the new city plan, transforming the old quarters into an archaeological park, and dividing the new city into a residential, an administrative, and a commercial area.,[30] In World War II, the island, as Italian possession, was part of the Axis. It was controlled by Italian troops until the Italian surrender in 1943. On that occasion, 100 Italian officers who had refused to join the Germans were executed. British and German forces then clashed for control of the island in the Battle of Kos as part of the Dodecanese Campaign, in which the Germans were victorious. German troops occupied the island until 1945, when it became a protectorate of the United Kingdom, which ceded it to Greece in 1947 following the Paris peace treaty.

In the late 1920s about 3,700 Turks lived in Kos city, slightly less than 50% of the population, settled mainly in the west part of the city.[31]

The island is part of a chain of mountains from which it became separated after earthquakes and subsidence that occurred in ancient times. These mountains include Kalymnos and Kappari which are separated by an underwater chasm c. 70 metres (230 ft) (40 fathoms deep), as well as the volcano of Nisyros and the surrounding islands.[citation needed]

The main religion practiced is Greek Orthodoxy. Kos has one of the four cathedrals in the entire Dodecanese. There is a Roman Catholic church on the island. There is a mosque for the Turkish-speaking Muslim community. The Synagogue is no longer used for religious ceremonies as the Jewish community of Kos was targeted for destruction by occupying Nazi forces in World War II. It has, however, been restored and is maintained with all religious symbols intact and is now used by the Municipality of Kos for various events, mainly cultural.

View of the municipal market, built in 1934–35 by architect Rodolfo Petracco

Street of Kos town

The ancient market place of Kos was considered one of the biggest in the ancient world. It was the commercial and commanding centre at the heart of the ancient city. It was organized around a spacious rectangular yard 50 metres (160 ft) wide and 300 metres (980 ft) long. It began in the Northern area and ended up south on the central road (Decumanus) which went through the city. The northern side connected to the city wall towards the entrance to the harbour. Here there was a monumental entrance. On the eastern side there were shops. In the first half of the 2nd century BC, the building was extended toward the interior yard. The building was destroyed in an earthquake in 469 AD.

In the southern end of the Market, there was a round building with a Roman dome and a workshop which produced pigments including "Egyptian Blue". Coins, treasures, and copper statues from Roman times were later uncovered by archeologists. In the western side excavations led to the findings of rooms with mosaic floors which showed beastfights, a theme quite popular in Kos.[34]

The ancient physician Hippocrates is thought to have been born on Kos, and in the center of the town is the Plane Tree of Hippocrates, a dream temple where the physician is traditionally supposed to have taught. The limbs of the now elderly tree are supported by scaffolding. The small city is also home to the International Hippocratic Institute and the Hippocratic Museum dedicated to him. Near the Institute are the ruins of Asklepieion, where Herodicus taught Hippocrates medicine.

^Iliad ii.676, from "Kos, the city of Eurypylus, and the Calydnae isles", under the leaders Phidippos and Antiphos, "sons of the Thessalian king". It is unclear whether Homer is describing cultural affiliations of his own time or remembered traditions of Mycenaean times.